BMR Calculator – Free Basal Metabolic Rate

What is BMR and how is it calculated?

Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic physiological functions like breathing, circulation, and cell production while at complete rest. It is calculated using the Mifflin-St Jeor equation, which takes into account your gender, age, height, and weight.

How to use the BMR Calculator

Select your gender, enter your age, height (cm), and weight (kg), then click "Calculate". The calculator instantly displays your Basal Metabolic Rate in kcal per day – the energy your body burns at rest.

How BMR is calculated

This calculator uses the Mifflin-St Jeor formula: For men – 10 × weight (kg) + 6.25 × height (cm) – 5 × age (y) + 5; For women – 10 × weight (kg) + 6.25 × height (cm) – 5 × age (y) – 161. This equation is considered the most accurate for estimating BMR in healthy individuals.

Example calculation

For a 30‑year‑old woman, 165 cm tall, weighing 60 kg, BMR = 10 × 60 + 6.25 × 165 – 5 × 30 – 161 = 1321.25 kcal/day. That’s the amount of calories her body burns at complete rest.

Frequently Asked Questions

What is the difference between BMR and TDEE?

BMR is the calories you burn at total rest. TDEE (Total Daily Energy Expenditure) includes BMR plus energy used for physical activity and digestion. To estimate TDEE, multiply your BMR by an activity factor.

Can BMR change over time?

Yes, BMR varies with age, weight, muscle mass, and hormonal factors. Generally, BMR decreases with age as muscle mass tends to decline, but building muscle through exercise can increase it.